The invention resides in an apparatus for guiding surgical instruments for endoscopic surgery while the instruments are mounted as a shank which is supported so as to be pivotable about a so-called invariant point.
During laparoscopic surgery, the surgeon operates on the basis of a monitor picture. An endoscope with a camera and the instruments required for the operation are inserted into the body of a patient, for example, by a trocar. The endoscope and the instruments are so supported that they can be moved only about the so-called invariant point which is within the body of the patient and which represents the trocar insertion point. In this way, the endoscopic system and the instruments each can be controlled with the same positioning system. However, the camera should be oriented, for example, by the CCD chip of a camera, in a direction toward the floor, that is, the support point of the surgeon, independently of the movement of the instruments. If the monitor picture would be turned, the spatial orientation of the surgeon during endoscopic surgery may be detrimentally affected.
WO 94/21188 discloses such a mechanical guide system for endoscopic surgery wherein the instrument is inserted into a body for a surgical procedure or for observation through the sleeve of a trocar and the instrument effecter, which is mounted at the end of a shaft, is movable within the body cavity in all degrees of freedom; the invariant point however is maintained. In the system described a camera is mounted as an effecter on the free end of the laparoscope and is movable linearly with the laparoscope shaft.
Endoscopes usually have a prism arranged at their front end which is usually inclined by 30.degree. whereby rotation of the endoscope permits observing an area within the body. Upon rotation of the effecter for observing the surrounding area within the body, a camera rigidly supported on the endoscopic as shown in WO 94/21188 provides, with the respect to the position of the surgeon, that is, the floor, a proper picture orientation only for the horizontal and center position of the camera. In all other positions of the CCD chip in the camera, the spatial orientation is changed, that is, the camera and the endoscope must be especially controlled so as to prevent rotation of the monitor picture. This requires a substantial technical effort. The rotation of the endoscope consequently detrimentally affects the orientation for the surgeon, for example, in the abdominal cavity, since the "top" and "bottom" of the camera picture may be different from the actual top and bottom with respect to the position of the surgeon.
Another guide system for a surgical observation apparatus is disclosed in DE-GM 94 16 957. The system described therein is principally similar to the above described system so that the same comments apply.
It is therefore the object of the present invention to provide an apparatus for guiding surgical instruments particularly for use in endoscopic surgery wherein, during rotation of the endoscope for the spatial observation in a body cavity, the picture transmitted to the camera and consequently, to the monitor screen is always properly oriented so that the "top" and "bottom" are properly presented.